Preparation of acrylates



nited States Patent 2,778,843 PREPARATION OF ACRYLATES Andrew Neuman,North Hiils, Harry T. Neher, Bristol, and Edward H. Specht,Philadelphia, Pa., assignors to Robin & Haas Company, Philadelphia, Pa.,a corporation of Delaware N0 Drawing. Application January 21, 1953,Serial No. 332,506

12 Claims. (Cl. 260-436) This invention deals with the preparation ofesters of acrylic acid by reacting together a monohydric alcohol of atleast three carbon atoms, carbon monoxide, nickel carbonyl, acetylene,and water.

This application is a continuation-in-part of our application Serial No.239,618, filed July 31, 1951, now abandoned, which is in turn acontinuation of our application Serial No. 173,482, filed July 12, 1950,now U. S. Patent No. 2,582,911, issued January 15, 1952.

It has been shown that at temperatures of about 40 C. there can bereacted acetylene, nickel carbonyl, an acid, and an alcohol to formacrylic esters of the alcohol. Various by-products inevitably form inthis reaction, such as propionates, vinyl-propionates, and othercompounds in the formation of which the hydrogen which shouldtheoretically be evolved is consumed. In another approach it was foundthat acetylene, carbon monoxide, and some alcohols can be reacted atl50-180 C. under high pressure in the presence of such nickel salts asnickel iodide or bromide. At these temperatures the nickel salt isdepleted, by reaction with carbon monoxide, organic halogen compoundsare formed, acetylene is decomposed and also polymerized, and hazardsand difiiculties due to handling acetylene at high pressures andtemperatures are encountered. Furthermore, it has been found thatreaction of tertiary alcohols and allylically unsaturated alcohols underthese conditions is unsatisfactory or even impracticable.

Even at lower temperatures the stoichiometric reaction of tertiaryalcohols or allylically unsaturated alcohols, acetylene, nickelcarbonyl, and acid is not fully satisfactory. Acid tends to promotedehydration of the tertiary alcohols and the reaction of allylicallyunsaturated alcohols does not always run smoothly and regularly. If amixture of an alcohol, nickel carbonyl, and an acid is treated with amixture of acetylene and carbon monoxide in required proportions, noreaction ensues, In our parent case, we have shown, however, that thereaction of an alcohol, acetylene, and carbon monoxide at moderatetemperatures can be effected by imposing it upon the stoichiometricreaction of acetylene, nickel carbonyl, alcohol, and acid. In eifect thetwo reactions go on simultaneously in the same reaction mixture.

It has now been found that a further improvement is obtained by firsteffecting the reaction of a monohydric alcohol of at least three carbonatoms, particularly of a tertiary or allylically unsaturated alcohol,acetylene, and nickel carbonyl in the presence of a lower monocarboxylicacid such as acetic or acrylic acid and then, while this first reactionis being carried on, bringing into the reacting mixture and therereacting together one of the said alcohols, acetylene, carbon monoxide,nickel carbonyl, and water to form an acrylic ester of said alcohol andcontinuing the reaction of these five materials. It will be noted thatin this improvement addition of acid is discontinued as soon as reactionof the above five materials has been established.

This is of decided and peculiar advantage for forming acrylic esters ofthe tertiary alcohols and also of allylically unsaturated alcohols. Themethod may, however, be applied to other alcohols, such as alkanols ofthree to twelve carbon atoms, to ether alcohols, and to alicyclicalcohols. It is a highly effective method when terpenic alcohols arereacted. In general the method of this invention can be applied to anyalcohol of the formula ROH, where R is an alcohol residue of three totwelve carbon atoms, particularly a hydrocarbon residue.

The process is advantageously applied to the allylically unsaturatedalcohols, such as allyl, Z-methallyl, Z-ethallyl, Z-butallyl,2-phenylallyl, 2-chloroallyl, neopentylallyl, crotyl, 3-ethallyl,3-butallyl, cinnamyl, and the like, particularly those of not overtwelve carbon atoms. Many of these may be represented by the formulawhere R represents hydrogen, an alkyl group, particularly one of notover four carbon atoms, or a phenyl group and R represents hydrogen,phenyl, chlorine, or an alkyl group, particularly one of not over fivecarbon atoms.

The process is also advantageously applied to tertiary alcohols. Ofthese the readily available ones are tertiary butyl and tertiary amyl.

There may also be reacted other alcohols, such as isopropyl, n-butyl,hexyl, octyl, 2-ethylhexyl, isononyl, dodecyl, and so on, althoughusually without marked advantage. On the other hand cyclic alcohols areoften desirably reacted by the process of this invention to yieldacrylic ester. Mixed terpineols may be used or single alcohols such asa-terpineol. This process can also be successfully applied tocyanalkanols, chloroalkyl alcohols, ether alcohols, glycols, and otheralcohols having a functional group in addition to the hydnoxyl group.For any given alcohol there can be readily found the best proportions,temperatures, or adjustment for operating the reaction of this inventionat a high level of carbon monoxide utilization.

Theoretically the amount of Water required is equivalent to the nickelcarbonyl. Practically it has been found desirable to operate ordinarilyusing about to 400% of this theoretical quantity of water. In the caseor" such alcohols as isobutyl, octyl, decyl, and dodecyl 200% to 600% oftheory is desirable to carry the process at a good level of carbonmonoxide utilization.

The ratio of carbon monoxide to nickel carbonyl should be between 20:80and 70:30 with reference to the CO or carbonyl supplied by each of thesesubstances. Preferably 40 to 60 mole percent of the total CO is suppliedby the carbon monoxide.

Addition of acetylene is proportioned to the total CO or total carbonylfrom both carbon monoxide and nickel carbonyl. Operative proportions ofacetylene should best be within a tenth mole of theory, i. e., fromabout 0.9 mole to 1.1 moles of acetylene per mole of total CO. A ratiofrom 1.02:1 to 1.05:1 is usually optimum.

It will be noted that acid is actually added only at the start of theoperation. There can be used any acid which reacts with nickel carbonylin the reaction mixture to form a nickelous salt and which at the sametime makes available for reaction the carbonyl therefrom. The acid maybe a lower monocarboxylic acid, acids up to four carbon atoms beingeffective informing nickel salts and liberating the carbonyl content ofthe nickel carbonyl. It is generally best to use acrylic acid or aceticacid. Other organic acids such as propionic, methacrylic, or butyric canbe used, particularly when the alcoholbeing used is allylicallyunsaturated. With other alcohols a reactive strong acid may be chosen.The cheapest and best of these is hydrochloric acid. This strong acidmay be used at the start with primary, secondary, or even tertiaryalcohols, although strong acids tend to promotedehydration of sometertiary alcohols.

Acid is supplied only long enough to cause the stoichiometric reactionof acid, nickel carbonyl, alcohol, and acetylene. After this reactionhas become established, the reaction of nickel carbonyl, carbonmonoxide, alcohol and water is brought about and addition of acid isdiscontinued.

An excess of alcohol with reference to either total CO or acetylene isadvantageous, but not essential. Excess alcohol serves as a diluent andcan be recovered from the reaction mixture. Usuallythe alcohol is usedin a proportion equivalent to thetotal CO up to 100% excess, althoughlarger excesses maybe used when desired.

There may also be used an inert organic solvent, such as acetone, methylethyl ketone, dioxane,,benzene, toluene, and mixtures of such solvents.

Acetylene and carbon monoxide used in the process should be at least lowin oxygen and preferably essentially free of oxygen. For stable,continuous operation these gases should contain less than one halfpercent of oxygen. Acetylene should be relatively free of lower valencecompounds of phosphorus and arsenic and without appreciable sulfurcontent. Purification by conventional methods is sufficient to yield asatisfactory, non-contaminating gas.

Inert gases such ascarbon dioxide, nitrogen, or hydrogen act merely asdiluents. Commercial sources of acetylene or carbon monoxide may thus beused with no more than simple precautions.

The temperature of the reaction mixture may be between 30 and 90 C. andis preferably between 50 and 70 C. Cooling is usually necessary tomaintain the reaction mixture within the most desirable ranges oftemperature.

The reaction takes place without the need of added pressure. In somecases reaction proceeds actively enough to cause the pressure within thereactor to be below atmospheric. There are other situations where thepressure may be advantageously maintained above atmospheric.

At'the start of the reaction it is desirable to sweep air from thereaction vessel with an inert gas, such as nitrogen. This gas. is, ofcourse, soon displaced with acetylene and the reaction mixture isthereafter kept under an atmosphere composed of .acetyleneand carbonmonoxide.

The reaction vessel is charged at the start with alcohol, solvent, ifused, nickel carbonyljand acid. Acetylene is run into the charge.Reaction may begin spontaneously or be initiated by warming the mixture.With start of the reaction there is a rise in temperature anddevelopment of color. Alcohol, nickel carbonyl, acid, and acetylene maythen be passed into the mixture in about stoichiometric proportions orwith alcohol or water in excess, as has been indicated, to establish thestoichiometric reaction. Thereupon carbon monoxide is introduced and'the addition of acid is discontinued. The proper rates of flow arereached and the reaction continued with alcohol, water, acetylene,carbon monoxide, and nickel carbonyl.

If the reactionis run batchwise, the flow of materials is discontinuedat the proper time. There is usually some nickel carbonyl in thereaction mixture. This can be consumed by continuing the flow ofacetylene, which together with excess alcohol and acid (acrylic acid maybe added, if necessary) forms ester.' If the reaction is runcontinuously, reaction mixture is taken off in proportion to the addedmaterials. This mixture may likewise be treated to consume the lasttrace of nickel carbonyl.

The reaction mixture is worked up, conveniently by washing with water toseparate ester and nickel salt. The nickel can be recovered andreconverted to nickel carbonyl which is returned'to the process; Thepart containing 4 the ester is appropriately worked up, usually throughdistillation.

Thus, the process of this invention is carried out by first reacting agiven alcohol, acetylene, nickel carbonyl, and acid, particularly alower monocarboxylic aliphatic acid, a reaction here termed thestoichiometric reaction, then adding to this reacting mixture and therereacting between 30 and C. the said alcohol, carbon monoxide, acetylene,nickel carbonyl and water. The reaction is advantageously runcontinuously.

The following examples are illustrative of this invention. Parts are byweight.

Example 1 The reactor system was so arranged that all reactants were fedcontinuously into the reaction mixture stream just prior toits passagethrough a pump which rapidly circulated the mixture through awater-jacketed tube, into a surge vessel, and back to the pump. Aninitial volume (ca. 1800 cc.) of reaction mixture from a previous run,made up of 782 grams of tertiary butyl acrylate, 135

grams of acrylic acid, 576 grams of tertiary butanol, 186 grams ofnickel acrylate, the remaining balance of 96 grams consisting of waterand high boiling organic residues, was charged to the empty reactor.This allowed sufiicient volume for circulation. The system was renderedsubstantially air-free by passing through it about 0.5 cubic foot ofnitrogen. The circulation pump was started and reactant feeds wereintroduced at the following rates: acetylene, 49.4 grams per hour;nickel carbonyl, 82.1 grams per hour; and tertiary butanol, 138.5 gramsper hour. After twenty minutes, water was introduced to the reactionmixture stream at the rate of 29.2 grams per hour, and additionaltertiary butanol was simultaneously introduced to correspond with thetotal feed rate of 308 grams per hour. The above feeds, at theirrespective rates, were continued for twenty minutes when the reactionmixture became a deep brown color. The acetylene rate was then increasedto 94.1 grams per hour and carbon monoxide gas was introduced at therate of 43.4

grams per hour and continued at this level for ten minutes.

carbon monoxide gas to 65 grams per hour and flow of gases wasmaintained at this level for twenty minutes at which time the finalrates were adjusted to supply acetylene at grams per hour and carbonmonoxide gas at 80.2 grams per hour. Reaction was maintained for aperiod of about six hours until the nickel carbonyl feed reseivoir wasemptied. During this period the temperature of the reaction mixture wasmaintained at 70 -74 C. by cooling. After the reactor became filled to apredetermined volume, the level was held constant by continuouswithdrawal from the surge vessel. The pressure in the system wasessentially atmospheric with the prevailing reactant ratios (molar)consistently corresponding to 69% excess water, 9% excess tertiarybutanol, and 4.5% excess acetylene based on carbonyl or carbon monoxideequivalent to the nickel carbonyl and carbon monoxide gas. A total of5124 grams of reaction mixture, containing suspended nickel acrylate,was obtained. After removal of unreacted nickel carbonyl by passing astream of 31 grams per hour of acetylene, the product was filtered. Thefiltrate was washed with about 5800 grams of water. Fractionaldistillation of the washed organic material and steam distillation ofthe aqueous layer, to which the nickel salt filter cake was added, gavea total of 2227 grams of ester, 782 grams of which was precharged, and636 grams of free acrylic acid, grams of which was precharged. A portionof the ester distillate Was waShed with sodium Found t-Butyl Acrylate1.4090 (literature).

122 G./760 mm. (literature)- 438.3 (theory).

(theory).

Example 2 An apparatus was constructed with a pump, a vertical tubesurrounded with a jacket through which cooling water could becirculated, and a surge vessel. The pump was arranged to receivereactants and pass them into the vertical tube from which they flowed tothe surge vessel. The surge vessel was arranged so that a constantvolume remained in it and reaction mixture therefrom overflowed to areceiver.

At the start the reactor was flushed with nitrogen and the tube wascharged with 1865 parts of reaction mixture from a previous run, thismixture containing tertiary butyl acrylate, tertiary butanol, acrylicacid, nickel acrylate, water, and organic residue of a higher boilingpoint range than that for tertiary butyl acrylate. The pump was startedand reactants were introduced into the reaction system as follows:acetylene at the rate of 49.4 parts by weight per hour; nickel carbonylat the rate of 81 parts per hour; and tertiary butanol at the rate of138.5 parts per hour. After twenty minutes, water was introduced to thereaction mixture at the rate of 30.1 parts per hour and additionaltertiary butanol was introduced to correspond with the total rate of 422parts per hour. When the reaction mixture changed to a deep brown colorafter 15 minutes at the described reactant rate, the acetylene rate wasincreased to 94.1 parts per hour and carbon monoxide gas was introducedat the rate of 43.4 parts per hour. Reactant rates were maintained atthese levels for ten minutes and then the acetylenev feed was increasedto 103.8 parts per hour and carbon monoxide gas to 53.2 parts per hourand then further increased after ten minutes to an acetylene rate of115.3 parts per hour and a carbon monoxide rate of 65 parts per hour.The final rates of acetylene (130 parts per hour) and carbon monoxidegas (80.2 parts per hour) were adjusted twenty minutes after theprevious rate adjustments. Reaction was maintained for a periodtotalling about six hours at which time the nickel carbonyl supply wasexhausted. During this period the temperature of the reaction mixturewas maintained at 75-76 C. by cooling. The pressure in the reactorsystem was essentially atmospheric.

A total of 5 708 parts reaction mixture was collected and then treatedwith additional acetylene to react with the unreacted nickel carbonyl.The resulting mixture was washed with water and the respective layerswere distilled. A total of 1783 parts of tertiary butyl acrylate wasobtained. This corresponds to a yield of. 66.2% based on the totalcarbon monoxide from nickel carbonyl and carbon monoxide gas less thattheoretically required to supply acrylic acid for the correspondingnickel acrylate. The balance of the carbon monoxide was mainly accountedfor as acrylic acid.

Example 3 The same system employed in the preparation of t-bu-tylacrylate was used with allyl alcohol in place of t-butanol for thepreparation of allyl acrylate.

The reactor system was charged with an initial volume of reactionmixture consisting of 863 parts of allyl acrylate, 217 parts of acrylicacid, 610 parts of allyl alcohol, 237 parts of nickel acrylate, and 48parts consisting of water and high boiling organic residue from aprevious preparation. After the system had been flushed with nitrogen,the circulation pump was started and the reactants were introduced. Therates of addition of the reactant were: acetylene, 49.4 parts per hour;nickel carbonyl, 81 parts per hour; and allyl alcohol, 152 parts perhour. After twenty minutes water was introduced at the rate of 30.4parts per hour and the allyl alcohol feed rate was increased to a totalof 360 parts per hour. The reaction mixture became a dark color afterabout 30 minutes, when the acetylene rate was increased to 94.1 partsper hour. Simultaneously carbon monoxide was introduced at a rate of43.4 parts per hour. The feed rate of acetylene and carbon monoxide weresimultaneously increased at intervals to a maximum rate of parts perhour and 80.2 parts per hour respectively. Reactan-t rates werecontinued at the following molar ratios, based on total carbonyl orcarbon monoxide from both the nickel carbonyl and the carbon monoxidegas:

start-up and for increasing the reactant ratio was:

Operation (Rates as parts per hour) Total Elapsed Time, Hours Startfeeds: Ni(C0)4, 81; Allyl alcohol, 152; OzH

Introduce 00 gas, 43.4; Increase 02H; to 94.1.

Increase CO gas to 53.2; Increase C2H2 to 103.8.

- Incrcase 00 gas to 65.0; Increase 0 H; to 115.3.

Increase 00 gas to 80.2; Increase 02112 to 130.

Shut dtown feeds, the N i(OO)4 feeder reservoir being emp y.

The temperature of the reaction mixture was maintained at 69-70" C. bycooling. Th9 system was operated essentially at atmospheric pressurewith the liquid level maintained at a predetermined volume by continuouswithdrawal of reaction mixture which contained suspended nickelacrylate. The total reaction mixture collected was 5710 parts which wastreated with acetylene for removal of unreacted nickel carbonyl and thenwashed with a total of 5700 parts of water. A total of 1468 parts ofallyl acrylate and 441 parts of acrylic acid were obtained, allowing forester and acid precharged.

A portion of the ester distillate was purified by washing with asolution of potassium carbonate and water and redistilling. The mainportion of the distillate ester, collected at 55.5 57 C. at 60 mm.mercury pressure was found to have the following properties:

Found Allyl Acrylate Saponification N0 499. 6 500.4 (theoretical value).Acid N0." 0 0 (theoretical value).

34. 06 35.7 (theoretical value). 1. 4311 1.4320 (from the literature).

Example 4 A reaction vessel was equipped with a stirrer, a cooling coil,a thermometer, an inlet tube at the bottom for introduction of liquidand gaseous feeds, an outlet tube at the top for vent gases and anoverflow pipe to permit continuous withdrawal of reaction mixture.

The reaction system was swept with nitrogen and charged with 362 partsof n-butyl alcohol, 36 parts of acrylic acid and 36 parts of water.Reactants were then introduced as follows: acetylene, at the rate of27.3 parts per hour; nickel carbonyl, at the rate of 42.6 parts perhour, introduced as a 31.2% solution'in n-butyl alcohol. After twelveminutes reaction began as shown by formation of a brown color in themixture, a sudden temperature rise and complete absorption of acetylene.The temperature was allowed to rise until it had reached 55 C., at whichlevel it was maintained thereafter by cooling. At twenty minutes theacetylene rate was increased to 49.4. Iugggduce H2O feed, 30.4; IncreaseAllyl alcohol to 41.1 parts per hour and carbon monoxide was introducedat the rate of 14.0 parts per hour (33% carbon monoxide utilization). Atten-minute intervals the rates of acetylene and carbon monoxide feedswere increased until at fifty minutes these rates were 54.6 and 28.0parts per hour, respectively (50% carbon monoxide utilization). At sixtyminutes water was introduced at the rate of 36 parts per hour and wascontinued at this rate for the remainder of the reaction period. At 120minutes the acetylene and carbon monoxide feed rates were increased to60.6 and 34.2 parts per hour, respectively; at 150 minutes they wereincreased to 68.1 and 42.0 parts per hour, respectively; and at 210minutes, to 78.0 and 52.1 parts per hour, respectively. These finalrates corresponded to 65% carbon monoxide utilization, i. e., 65 of thetotal available carbon monoxide was supplied as carbon monoxide gas, theremaining 35 as nickel carbonyl. At 240 minutes an additional supply ofn-butyl alcohol was introduced at the rate of 169 parts per hour,

this rate being maintained for the remainder of the reaction period. At300 minutes the reaction mixture had reached the top of the overflowtube and continuous withdrawal was started. At 360 minutes all reactantfeeds were discontinued and the reactor was drained.

Subsequently, the reaction vessel was swept out with nitrogen andcharged with the reaction mixture obtained above. Reactants wereintroduced as follows: acetylene, 27.3 parts per hour; nickel carbonyl,42.6 parts per hour, as a 31.2% solution in n-butyl alcohol; and water,36 parts per hour. At thirty five minutes the reaction began;immediately the acetylene feed rate was increased to 45 .5 parts perhour and carbon monoxide was introduced at the rate of 23.0 parts perhour. Thereafter, at fiveminute intervals the gas feed rates wereincreased in stages until at fifty minutes the rates were: acetylene,78.0 parts per hour and carbon monoxide, 52.1 parts per hour. Theserates correspond to a 65 carbon monoxide utilization. At sixty minutesan additional n-butyl alcohol feed was started at the rate of 183 partsper hour and the carbon monoxide utilization was raised to 67% byincreasing the acetylene and carbon monoxide feed rates to 82.0 and 56.0parts per hour, respectively. After a period of alternately high and lowvent rates, indicative of instability, absorption of gases ceased at 111minutes; the carbon monoxide and alcohol feeds were shut off and theacetylene feed was reduced to 27.3 parts per hour. At 117 minutes thereaction began again. The acetylene feed was raised to 78.0 parts perhour, carbon monoxide was introduced at 52.1 parts per hour, and theadditional alcohol feed was restored at 169 parts per hour. These rates,corresponding to 65% carbon monoxide utilization, were maintained forthe remainder of the reaction period. As before, the temperature washeld at 55 C. with cooling. Withdrawal of reaction mixture from theoverflow pipe was continuous throughout the reaction period.

At 360 minutes the nickel carbonyl and alcohol feeds were shut off. At380 minutes the carbon monoxide feed was shut off and five minutes laterabsorption of acetylene had ceased. The reaction mixture, a clear greensolution with a little solid nickel salt present, was drained from thereaction vessel. Previously withdrawn reaction mixture was returned tothe reaction vessel and acetylene was passed in until absorption ofacetylene and exothermic reaction ceased.

The reaction mixture was washed with water to remove nickel salts, withsodium carbonate solution to remove acidity and was then distilled.After a forerun which contained water, n-butyl alcohol and some n-butylacrylate, the main fraction containing essentially pure n-butyl acrylatewas taken at 86-87 C. under a pressure of 100 mm.

- Analyses. -Saponification number: calculated, 438; found, 441. Acidnumber: calculated, 0.0; found, 2.9. Bromine number: calculated, 15.6;found, 15.0. The yield of n-butyl acrylate, including that recoverablefrom the forerun, was 68.9%, based on the total carbon monoxideavailable for ester formation.

Example 5 The reaction system used was the same as that described forthe preparation of n-butyl acrylate. The reaction system was swept withnitrogen and charged with 360 parts of sec.-butyl alcohol, 10 parts ofacrylic acid, and 18 parts of water. The nickel carbonyl feeder wascharged With a solution containing 31.5% nickel carbonyl (by weight) insec.-butyl alcohol.

Reactants were introduced at the following rates: acetylene, 27.3 partsper hour and nickel carbonyl, 42.6 parts per hour. The reaction beganafter thirteen minutes, indicated by development of a brown color, aslow rise in temperature and a gradual decrease in the rate of vent gasevolution. The temperature of the mixture, originally at 28 C., wasallowed to rise until it reached 55 C., where it was maintainedthroughout the remainder of the reaction period. Thirty minutes afterthe feeds were started, the acetylene feed rate was increased to 41.1parts per hour and carbon monoxide was introduced at the rate of 14.0parts per hour. At sixty minutes water was introduced at the rate of 18parts per hour and was maintained at this rate for the remainder of thereaction period. The feed rates of acetylene and carbon monoxide wereperiodically increased at approximately hourly intervals until the finalrates of 68.1 and 42.0 parts per hour, respectively, were reached atabout 300 minutes; these rates corresponded to a carbon monoxideutilization of 60%. After operating for one hour at this level, thereaction was discontinued byshutting off all feeds. It was subsequentlyre-started by supplying acetylene at the rate of 27.3 parts per hour;nickel carbonyl at 42.6 parts per hour (in 31.5% solution, as describedabove), and water at 18 parts per hour. The reaction began withinfifteen minutes and at thirty minutes the acetylene feed rate wasincreased to 45.5 parts per hour and carbon monoxide was introduced atthe rate of 18.8 parts per hour. These rates were increased rapidly instages until at sixty minutes the rates were 68.1 parts of acetylene perhour and 42.0 parts of carbon monoxide per hour, corresponding to 60%carbon monoxide utilization. Additional alcohol was then supplied at therate of 129 parts sec.-butyl alcohol per hour. Withdrawal of reactionmixture from the top of the overflow pipe began and was carried outcontinuously for the remainder of the reaction period. After five hoursat the above conditions, the nickel carbonyl and alcohol feeds were shutoff. Twenty minutes later carbon monoxide ceased to be absorbed and thefeed was shut off. In an additional ten minutes exothermic reactionceased and acetylene was no longer absorbed. Unreacted nickel carbonylremaining in the previously withdrawn reaction mixture was used up bypassing in acetylene until no further absorption occurred.-

The reaction mixture was washed with water and with sodium carbonatesolution. The organic layer was distilled and after removal of a foreruncontaining water, sec.-butyl alcohol and some sec.-butyl acrylate, amain fraction was taken, boiling at 5 8-5 8.5 C. under a pressure of 50mm. This material was sec.-butyl acrylate; saponification number, 442;acid number, 0.0; bromine number, 14.95; calculated values are: 438, 0.0and 15.6, respectively. The total yield of sec.-butyl acrylate was67.0%, based on the total carbon monoxide available for ester formation.

Example 6 The reaction system, the same as that used in the preparationof n-butyl arcylate, was swept with nitrogen and charged with 370 partsof n-octyl alcohol, 36 parts of acrylic acid, and 36 parts of water. Thenickel carbonyl feeder was charged with a solution containing 30.8% byweight nickel carbonyl in n-octyl alcohol.

The reaction was started by introducing reactants at the followingrates: acetylene, 27.3 parts per hour and nickel carbonyl, 42.6 partsper hour. At ten minutes a brown color appeared in the mixture, thetemperature rose, and acetylene was completely absorbed. At twentyminutes carbon monoxide was introduced at the rate of 14.0 parts perhour with a simultaneous increase in the acetylene rate to 41.1 partsper hour; these rates corresponded to 33% carbon monoxide utilization.At ten-minute intervals the acetylene and carbon monoxide feed rateswere increased to the following stages:

Parts per hour Acetylene 45.5 Do 49.6

Do 54.6 Carbon monoxide 18.8

The temperature, initially at 24 C., was allowed to rise during thisperiod until it reached 55 C., where it was maintained thereafter bycooling.

Beginning at sixty minutes water was supplied at the rate of 36 partsper hour and this supply was continued for the remainder of the reactionperiod. At 120 minutes the gas feed rates were again increased to 60.6parts of acetylene per hour and 34.2 parts of carbon monoxide per hour.At 150 minutes additional alcohol was supplied at the rate of 240 partsof n-octyl alcohol per hour. Four hours after starting the reactioncontinuous withdrawal of reaction mixture was started from the top ofthe overflow tube. The feeds were continued for a total reaction periodof nine hours and were then shut off. Nickel carbonyl remaining in thereaction mixture was used up by passing in acetylene until absorption ofacetylene and exothermic reaction ceased.

The reaction mixture, a bright green slurry, was washed with water andwith sodium carbonate solution and was then distilled. The main fractiondistilled at 77-77.5' C./2.5 mm. It had a saponification number of 302(calculated, 305 and an acid number of 0.0. The total yield of n-octylacrylate was 73.7%, based on total carbon monoxide available for esterformation.

Example 7 The reaction system, the same as that described for thepreparation of n-butyl acrylate, was swept with nitrogen and chargedwith 415 parts of Z-ethoxyethanol, 36 parts of acrylic acid, and 72parts of water. The nickel carbonyl feeder was charged with a 28.4weight percent solution of nickel carbonyl in Z-ethoxyethanol.

Reactant feeds were started at the following rates: acetylene, 27.3parts per hour; nickel carbonyl, 42.6 parts per hour. Exothermicreaction began in eleven minutes accompanied by appearance of a browncolor in the mixture and absorption of acetylene. The temperature,initially at 27 C., was allowed to rise to 55 C. where it was maintainedby cooling. Carbon monoxide was introduced at twenty minutes along withadditional acetylene and periodic increases were made in the gas feedrates according to the following, schedule:

At 240 minutes water was supplied at the rate of 18 parts per hours,continuing for the remainder of the reaction period. An alcohol feed, inaddition to that supplied with the nickel carbonyl, was started andmaintained at the rate of 156 parts of Z-ethoxyethanol' per hour.Continuous withdrawal of reaction mixture from the overflow tube wasstarted at 300 minutes. The reaction was continued for a total reactiontime of twelve hours, at which time the reactant feeds were shut off.Removal of unreacted nickel carbonyl in the withdrawn reaction mixturewas accomplished by passing acetylene into the mixture until no furtherabsorption of acetylene occurred and exothermic reaction ceased.

The reaction mixture, a deep green solution with some light green nickelsalt suspended therein, was washed three times with volumes of waterequal to the volume of the original reaction mixture. By this means mostof the unreacted 2-ethoxyethanol was removed along with the nickel salt.Sodium carbonate was added to the last wash water to remove acidity.Distillation of the washed organic layer gave a very small forerun,followed by a main fraction of essentially pure 2-ethoxyethyl acrylate,boiling point 63 -63.5 C. under a pressure of 10 mm.; saponificationnumber, 388, calculated, 389; acid number, 0.0, calculated 0.0; brominenumber, 13.5, calculated, 13.9. Additional amounts of Z-ethoxyethylacrylate were recovered by distillation of the aqueous wash water. Thetotal yield of 2-ethoxyethyl acrylate was 75%, based on total carbonmonoxide available for ester formation.

Example 8 Parts Per Hour Carbon Monoxide Utilization, Percent AcetyleneCarbon Monoxide 0 (stoichiometrle) 27. 3 0.0 40 45. 5 18. 8 60 54. 6 28.0 60 68. l 42. 0 65 78. 0 52. 1 67 S2. 0 56. 0

The nickel carbonyl feed rate in this series was 426 parts per hour; thenickel carbonyl was supplied as a 30.0 weight percent solution in allylalcohol. Water was supplied at the rate of 18 parts per hour. Thetemperature was maintained at 55 C. with cooling.

Pertinent details for the separate reactions are summarized below:

First reaction period, six h0urs.-The reaction system, the same as thatdescribed for the preparation of n-butyl acrylate, was flushed withnitrogen and charged with 380 parts of allyl alcohol, 10 parts ofacrylic acid, and 18 parts of water.

The reaction was initiated in the usual manner by feeding acetylene andnickel carbonyl at the rates indicated above. An exothermic reaction,with the usual brown coloration, began in fifteen minutes. Carbonmonoxide and additional acetylene were introduced at thirty minutes, thefeeds rates corresponding to 50% carbon monoxide utilization. At the endof four hours the reaction was sufficiently stable for 50% carbonmonoxide utilization to be maintained. The reaction remained at thislevel for two hours at which time the feeds were shut off. The entirereaction mixture, 21 deep green. solution, was saved for the nextreaction.

Second reaction period, five hours-The reaction system, after flushingwith nitrogen was charged with the entire reaction mixture obtained asdescribed above.

Acetylene and nickel carbonyl were passed in at the specified rates. Theexothermic reaction was slow in starting and was aided by passing steamthrough the coils to raise the temperature from the initial C. up to C.The reaction began at fifty-five minutes. At sixty minutes carbonmonoxide was introduced with simultaneous increase in the feed rate ofacetylene, both rates then corresponding to carbon monoxide utilization.At ten-minute intervals the carbon monoxide utilization was advanced to50, 60 and 65% and after a thirty-minute interval to the finalutilization of 67% which was held for the remainder of the reactionperiod; the gas flow rates at these various stages have been summarizedabove. At the end of five hours the feeds were shut off. An aliquot ofthe reaction mixture was reserved for use as the initial charge for thenext reaction; the remainder was made free of nickel carbonyl by passingin acetylene until absorption and exothermic reaction ceased. Thisportion was then washed with water to remove nickel salts and most ofthe unreacted allyl alcohol and with sodium carbonate solution to removeacidity. The resulting organic layer was then distilled and after asmall forerun a main fraction of essentially pure allyl acrylate wastaken distilling at 55.5 57 C./ 60 mm. Saponification number, 503,calculated, 500; acid number, 2.3, calculated 0.0;

bromine number, 34.2, calculated 35.7. Some additional allyl acrylatewas recovered by distillation of the aqueous wash liquors.

Third, fourth and fifth reaction periods, five hours each.-In each casethe reaction system was charged with an aliquot of reaction mixture fromthe immediately preceding reaction. Exothermic reaction began withintwenty to thirty minutes and the carbon monoxide utilization was thenadvanced through the stages, 40, 50, 60 and 65 at ten-minute intervalsand was increased to 67% after a thirty-minute interval. At the end ofthe second reaction, the very large excess of allyl alcohol, resultingfrom the initial charge of allyl alcohol at the beginning of the series,had been reduced to the desired level, i. e., a excess, based on thetotal carbon monoxide available for ester formation. Thus, in the latterthree reaction periods it was necessary to provide allyl alcohol inaddition to that already being fed with the nickel carbonyl. The rate ofalcohol feed used was 118 parts per hour in these three reactionperiods.

The yields of allyl acrylate in this series were as follows, the yieldsbeing based on total carbon monoxide available for ester formation:

Percent Second reaction 66 Third reaction 72 Fourth reaction 71 Fifthreaction 73 Example 9 The reaction system, the same as that describedfor the preparation of n-butyl acrylate, was swept with nitrogen andcharged with 382 parts of methallyl alcohol, 10 parts of acrylic acid,and 18 parts of water. The nickel carbonyl feeder was charged with asolution containing 128 parts of nickel carbonyl and 300 parts ofmethallyl alcohol; addition solution was charged as required.

A flow of acetylene was started at the rate of 27.3 parts per hour andnickel carbonyl solution was fed at the rate of 142 parts per hour. Ateleven minutes a brown color appeared, the temperature rose (initiallyat 29 C.) and absorption of acetylene began. At twenty minutes thetemperature had reached 50 C. The flow of acetylene was then raised to arate of 41.1 parts per hour and carbon monoxide was introduced at a rateof 14.0 parts per hour. The temperature was allowed to rise to C. andwas maintained there by cooling. At forty minutes the flow rates ofacetylene and carbon monoxide were increased to 45.5 and 18.8 parts perhour, respectively. Nine minutes later absorption of gases ceased and itwas necessary to shut 01f the flow of carbon monoxide and reduce theflow rate of acetylene to 27.3 parts per hour until the stoichiometricreaction had started; the acetylene and carbon monoxide rates were thenrestored to 41.1 and 14.0 parts per hour, respectively. At sixty minuteswater was supplied to the reaction system at the rate of 18 parts perhour. Two additional attempts were made to increase the flow rates asindicated above but without success. The temperature of the reactionmixture was then allowed to rise until it had reached C. At thistemperature it was found possible to increase the flow rates, in fourstages at intervals of fifteen to twenty minutes, to 60.6 parts ofacetylene per hour and 34.2 parts of carbon monoxide per hour, theserates corresponding to 55% carbon monoxide utilization.

With the addition of a feed of methallyl alcohol at the rate of 86 partsper hour, to provide together with the alcohol supplied from the nickelcarbonyl feeder a 50% excess of alcohol based on total carbon monoxideavailable for ester formation, the reaction under the above describedconditions could be carried out indefinitely with continuous withdrawalof reaction mixture from the overflow tube.

After six hours of operation a portion of the reaction mixture wastreated with acetylene to remove the last traces of nickel carbonyl. Themixture was washed with Water to remove nickel salts and with sodiumcarbonate to remove acidity. The organic layer was distilled and afterremoval of a forerun containing methallyl alcohol water, and somemethallyl acrylate, a main fraction of essentially pure methallylacrylate was taken at 6869.5 C./50 mm. The yield of methallyl acrylatewas 65%, based on the total carbon monoxide available for esterformation.

Example 10 The alcohol used in this preparation was about 82% (byweight) capryl alcohol, the remaining 18% being largely methyl hexylketone.

The reaction system, the same as that used in the preparation of n-butylacrylate, was charged with 365 parts of capryl alcohol, 10 parts ofacrylic acid, and 18 parts of water. The nickel carbonyl feeder wascharged with a 31.0% (by weight) solution of nickel carbonyl in caprylalcohol.

Acetylene was introduced at the rate of 27.3 parts per hour and nickelcarbonyl solution, at the rate of 137 parts per hour. Reaction began inthirty minutes and at thirty five minutes the acetylene feed rate wasraised to 41.1 parts per hour and carbon monoxide was introduced at therate of 14.0 parts per hour, the temperature of the mixture at this timebeing 37 C. Absorption of gases ceased almost immediately; the carbonmonoxide feed was shut oif and the acetylene feed rate was decreased to27.3 parts per hour. When the stoichiometric reaction had started again(in about five minutes), it was allowed to proceed until the temperaturehad risen to 55 C. At sixty minutes a continuous feed of water wasstarted at the rate of 18 parts per hour. Carbon monoxide was againintroduced as above, along with additional acetylene. Thereafter, atintervals of about thirty minutes, the carbon monoxide feed rate wasadjusted in the following stages: 18.8, 23.0 and 28.0 parts per hour;the corresponding acetylene feed rates were 45.5, 49.6 and 54.6 partsper hour.

At three hours after starting the initial reactant feeds an additionalfeed of capryl alcohol was started at the rate of 262 parts per hour tomaintain thereafter a con stant excess of alcohol. Withdrawal ofreaction mixture from the overflow tube began at 4.75 hours.

After a total reaction time of nine hours the nickel carbonyl supply wasshut off. Twenty minutes later, when the vent rate started to rise, theflow of carbon monoxide was shut off. Acetylene absorption continued forfive minutes. Reaction mixture which had been previously withdrawn wasmade free of nickel carbonyl by passing in acetylene until it was nolonger absorbed.

The reaction mixture was filtered to remove nickel acrylate, present inthe form of green crystals. The filtrate, a straw-colored liquid, waswashed with water and with sodium carbonate solution. It was thendistilled. The yield of capryl acrylate was 69.6%, based on total carbonmonoxide available for ester formation.

Example 11 The reaction system, the same as that'described for thepreparation of n-butyl acrylate, was swept with nitrogen and chargedwith 423 parts of cyclohexanol, parts of acrylic acid, and 18 parts ofwater. The nickel carbonyl feeder was charged with a 31.3 weight percentsolution of nickel carbonyl in methyl ethyl ketone.

Acetylene was introduced at the rate of 27.3 parts per hour and nickelcarbonyl at the rate of 42.6 parts per hour. Acetylene absorptionstarted in thirty minutes and at forty minutes the acetylene feed ratewas increased to 41.1 parts per hour and a feed of carbon monoxide wasstarted at the rate of 14.0parts per hour. The temperature whichinitially was 26 C. was allowed to rise to 55 C. and was maintainedthere by cooling. At sixty minutes a continuous feed of water wasstarted at the rate of 18 parts per hour. Also beginning at sixtyminutes the gas feed rates were increased in stages at intervals of tenminutes. The rates at these various stages were as follows: Acetylene,45.5, 49.6, 54.6, 60.6 and 68.1 parts per hour; carbon monoxide, 18.8,23.0, 28.0, 34.2 and 42.0 parts per hour. The final rates correspondedto a carbon monoxide utilization of 60%.

At 135 minutes a flow of cyclohexanol was started at the rate of 352parts per hour to maintain thereafter a constant, 50% excess of alcohol,based on the total carbon monoxide available for ester formation.Overflow of reaction mixture, a green slurry, star-ted at 220 minutes.All feeds were continued for a total reaction period of six hours. Thelast traces of nickel carbonyl in the reaction mixture were removed bypassing in acetylene until absorption ceased.

The reaction mixture was filtered to remove nickel acrylate as a lightgreen, crystalline salt. The filtrate, brownish-green in color, waswashed with water and with sodium carbonate solution. Upon distillationa forerun was obtained, containing chiefly cyclohexanol with somecyclohexyl acrylate, and a main fraction consisting of essentially purecyclohexyl acrylate, distilling at 62- 63 C. under .a pressure of 4.5mm.

Saponification number, 364.2, calculated, 364. Acid number, 0.1,calculated, 0.0. Bromine number, 12.65, calculated, 12.95.

The yield of cyclohexyl acrylate, obtained from. both fractions, was73.5%, based on total carbon monoxide available for ester formation.

Example 12 The reaction system, the same as that described in thepreparation of n-butyl acrylate, was swept with nitrogen and chargedwith 360 parts of tertiary amyl alcohol, 10 parts of acrylic acid, and18 parts of water. The nickel carbonyl feeder was charged with a 31.3weight percent solution of nickel carbonyl in tertiary .amyl alcohol.

A flow of acetylene was started at the rate of 27.3 parts per hour.Nickel carbonyl solution was fed at the rate of 136 parts per hour. Theinitial temperature was 27 C. Within twenty minutes an exothermicreaction had started, accompanied by formation of a brown color in themixture. At thirty minutes the acetylene feed was being completelyabsorbed. The first attempt to introduce carbon monoxide, along withadditional acetylene failed but at sixty minutes absorption wasessentially complete. At this time a flow of water was started at therate of 18 parts per hour. At thirty-minute intervals ina parts per hourof carbon monoxide.

creases were made in the gas feed rates. The acetylene feed rates atthese various stages were 41.1, 45.5, 49.6, 54.6, 60.6, 68.1, 78.0 and82.0 parts per hour; the corresponding carbon monoxide feed rates were14.0, 18.8, 23.0, 28.0, 34.2, 42.0, 52.1 and 56.0 parts per hour. Thefinal rates given corresponded to 67% carbon monoxide utilization andwere reached at 270 minutes after starting the initial feeds. At thistime an additional feed of tertiary amyl alcohol was started at the rateof 235 parts per hour. The reaction temperature was held at 55 C. withcooling. Overflow of reaction mixture began at 315 minutes.

After a total reaction period of nine hours the reactant feeds were shutoff. Acetylene was passed into the reaction mixture to remove the lasttraces of nickel carbonyl. The reaction mixture, a green slurry, wasthen filtered to give a bright green salt cake and an amber coloredfiltrate. The filtrate was distilled at 3467 C./ 136 mm. to obtain adistillate and leaving behind a residue containing higher-boiling andnon-distillable by-products. The distillate contained tertiary amylalcohol, tertiary amyl acrylate. and free acrylic acid. The distillatewas washed with water and with sodium carbonate solution to removetertiary amyl alcohol. and the acrylic acid. A redistillation then gavea main. fraction of essentially pure tertiary amyl acrylate, boilingpoint 5860 C./36 mm. It had a saponification number of 398(calculated395) and an acid number of 1.2 (calculated 0).

The total yield of tertiary amyl acrylate was 51.7%, based on totalcarbon monoxide. available for ester formation.

Example 13 The alcohol used in this preparation was a mixture of terpenealcohols, containing a minimum of by weight a-terpineol The reactionsystem, the same as that de scribed for the preparation of n-butylacrylate was swept with nitrogen and charged with 418 parts ofa-terpineol, 36- parts of acrylic acid, and 18 parts of water. Thenickel carbonyl feeder was charged with a solution containing 257' partsof nickel carbonyl and 654 par-ts of a-terpineol.

Acetylene was passed into the charge at the rate of 27.3 parts per hour.and the nickel carbonyl feeder was started at the rate of 42.6 parts ofnickel carbonyl per hour. In. thirteen minutes absorption of acetylenebegan accompanied by a rise in temperature and appearance of'a browncolor in the mixture. At twenty minutes car bon monoxide was introducedat the rate of 14.0 parts per hour and the acetylene feed rate wassimultaneously raised to 41.1 parts per hour. These rates were increasedin three stages at ten-minute intervals to 54.6 and 28.0 parts per hourrespectively. The temperature, initially at 28 C., was at first allowedto rise and was then held at 55 C. with cooling. At sixty minutes a flowof water was started and maintained thereafter at the rate of 18 partsper hour. At thirty-minute intervals the gas feed rates were againraised in two stages, the final rates at minutes, being 68.1 parts perhour of acetylene and 42.0 At this time a feed of a-terpineol, inaddition to that supplied with the nickel carbonyl, was started at therate of 356 parts per hour. At 220 minutes continuous withdrawal ofreaction mixture was startedfrom the overflow tube.

' At the end of six hours the nickel carbonyl feeder was shut off.Absorption of the gas feeds continued for ten minutes, when the carbonmonoxide supply was shut off. Ten minutes later absorption of acetyleneceased and the reaction vessel was drained. The reaction mixture whichhad been previously withdrawn during continuous operation of thereaction was now returned to the reaction system for removal of the lasttraces of nickel carbonyl by passing in acetylene until absorption ofgas and exothermic reaction ceased.

The reaction mixture was washed with water to rem-ove nickel acrylateand then with sodium carbonate solution to remove acrylic acid.Considerable amounts of sodium carbonate were required, indicating thepresence of much free acrylic acid. Distillation of the washed organiclayer yielded .a mixture of a-terpinyl acrylate and a-terpineol; therewas no evidence of dehydration products of a-terpineol. The amount ofester present was determined from saponification numbers. The yield ofa-terpinyl acrylate, based on total carbon monoxide available for estervformation, was 43.5%. After fractional distillation a sample wasobtained for purposes of identification having the following properties:boiling point 71-73 C./0.15 mm.; saponification number, 269; acidnumber, 0.0; bromine number, 18.15; calculated values, 269, 0.0 and19.2, respectively.

We claim:

1. A process for preparing acrylic esters which comprises reactingtogether between 30 and 90 C. acetylene, nickel carbonyl, an acid whichforms a nickelous salt from the nickel carbonyl in the reaction mixtureand which makes available for reaction the carbonyl therefrom, the acidbeing used in a proportion suflicient to initiate reaction, and amonohydric alcohol of three to twelve carbon atoms, and, while thesesubstances are reacting, passing into the reaction mixture and therereacting between 30 and 90 C. acetylene, carbon monoxide, nickelcarbonyl, water, and a said alcohol.

2. A process for preparing acrylic esters which cornprises bringingtogether and reacting at a temperature between 30 and 90 C. acetylene,nickel carbonyl, a lower aliphatic monocarboxylic acid in a proportionapproximately equivalent to the nickel carbonyl, and a monohydricalcohol ROH, in which R is hydrocarbon residue of three to twelve carbonatoms, and, while these substances are reacting, bringing into thereaction mixture and there reacting at a temperature between 30 and 90C. acetylene, carbon monoxide, nickel carbonyl, water, and a saidalcohol.

3. A process for preparing acrylic esters which comprises bringingtogether and reacting between 30 and 90 C. acetylene, nickel carbonyl, alower aliphatic monocarboxylic acid in a proportion approximatelyequivalent to the nickel carbonyl, and a monohydric alcohol ROI-I, inwhich ,R is a hydrocarbon residue of three to twelve carbon atoms, andwhile these substances are reacting, bringing into the reaction mixtureand there reacting between 40" and 60 C. acetylene, carbon monoxide,nickel carbonyl, water, and a said alcohol, the ratio of the carbonmonoxide to the carbon monoxide of the nickel carbonyl being between :80and 70:30, the acetylene being supplied in a proportion of 0.9 to 1.1moles per carbonyl group, and the water being supplied in excess of thetotal carbonyl.

4. A process for preparing acrylic esters which comprises reactingtogether between and 90 C. acetylene,

nickel carbonyl, a lower monocarboxylic aliphatic acid in a proportionapproximately equivalent to the nickel carbonyl, and an alcohol from theclass consisting of allylically unsaturated monohydric alcohols of notover 12 carbon atoms, tertiary alkanols, and terpineols and passing intothe resulting reaction and there reacting between 30 and 90 C.acetylene, carbon monoxide, nickel carbonyl, water, and a said alcohol.

5. A process for preparing acrylic esters which comprises reactingbetween 30 and 90 C. acetylene, nickel carbonyl, acrylic acid in aproportion approximately equivalent to the nickel carbonyl, and analcohol from the class consisting of allylically unsaturated monohydricalcohols of not over 12 carbon atoms, tertiary alkanols, and terpineolsand passing into the resulting reaction mixture and there reactingtogether between 30 and 90 C. acetylene, carbon monoxide, nickelcarbonyl, water, and a said alcohol, the ratio of carbon monoxide to thecarbon monoxide of the nickel carbonyl being from 20:80 to :30, theacetylene being supplied from about 0.9 to 1.1 moles per carbonyl group,and the water being supplied in a proportion at least equivalent to thenickel carbonyl.

6. A process for preparing acrylic esters of allylically unsaturatedalcohols which comprises reacting between 30 and C. acetylene, nickelcarbonyl, acrylic acid in a proportion approximately equivalent to thenickel carbonyl, and an allylically unsaturated alcohol of not over 12carbon atoms and passing into the resulting reaction mixture and therereacting together between 30 and 90 C. acetylene, carbon monoxide,nickel carbonyl, water, and a said alcohol, the ratio of carbon monoxideto the carbon monoxide of the nickel carbonyl being from 20:80 to 70:30,the acetylene being supplied from about 0.9 to 1.1 moles per carbonylgroup, and the water being supplied in a proportion at least equivalentto the nickel carbonyl.

7. The process of claim 3 in which the alcohol is allyl alcohol.

8. The process of claim 3 in which the alcohol is Z-methallyl alcohol.

9. A process for preparing acrylic esters of tertiary alkanols whichcomprises reacting between 30 and 90 C. acetylene, nickel carbonyl,acrylic acid in a proportion approximately equivalent to the nickelcarbonyl, and a tertiary alkanol and passing into the resulting reactionmixture and there reacting together between 30 and 90 C. acetylene,carbon monoxide, nickel carbonyl, water, and a said alcohol, the ratioof carbon monoxide to the carbon monoxide of the nickel carbonyl beingfrom 20:80 to 70:30, the acetylene being supplied from about 0.9 to 1.1moles per carbonyl group, and the water being supplied in a proportionat least equivaalent to the nickel carbonyl.

10. The process of claim 9 in which the alcohol is tertiary butylalcohol.

11. The process of claim 9 in which the alcohol is tertiary amylalcohol.

12. A process for preparing an acrylic ester of ot-terpineol whichcomprises reacting between 30 and 90 C. acetylene, nickel carbonyl,acrylic acid in a proportion approximately equivalent to the nickelcarbonyl, and a-terpineol and passing into the resulting reactionmixture and there reacting together between 30 and 90 C. acetylene,carbon monoxide, nickel carbonyl, water, and a-terpineol, the ratio ofcarbon monoxide to the carbon monoxide of the nickel carbonyl being from20:80 to 70:30, the acetylene being supplied from about 0.9 to 1.1 molesper carbonyl group, and the water being supplied in a proportion atleast equivalent to the nickel carbonyl.

References Cited in the file of this patent UNITED STATES PATENTS NeherIan. 15, 1952 Albrecht et al. Sept. 29, 1953 OTHER REFERENCES

1. A PROCESS FOR PREPARING ACRYLIC ESTERS WHICH COMPRISES REACTINGTOGETHER BETWEEN 30* AND 90*C. ACETYLENE, NICKEL CARBONYL, AN ACID WHICHFORMS A NICKELOUS SALT FROM THE NICKEL CARBONYL IN THE REACTION MIXTUREAND WHICH MAKES AVAILABLE FOR REACTION THE CARBONYL THEREFROM, THE ACIDBEING USED IN A PROPORTION SUFFICIENT TO INITIATE REACTION, AND AMONOHYDRIC ALCOHOL OF THREE TO TWELVE CARBON ATOMS, AND, WHILE THESESUBSTANCES ARE REACTING, PASSING INTO THE REACTION MIXTURE AND THEREREACTING BETWEEN 30* AND 90*C. ACETYLENE, CARBON MONOXIDE, NICKELCARBONYL, WATER, AND A SAID ALCOHOL.